The present invention relates to a balloon catheter used in carrying out an examination or therapy of affected parts inside blood vessels and, more particularly, to a balloon catheter which is effective for use in angiography of abdominal arteries and veins and portal veins.
Generally, a catheter is a tubular device which is inserted into blood vessels, urethrae, etc. for therapy, diagnosis and the like. The catheter is provided with a balloon on the periphery of the tip portion.
This balloon catheter is usually provided with a main passage having an opening at the tip portion of a catheter body for injection of drugs such as contrast medium into blood vessels and the like and an auxiliary passage for injection of gates, liquids, etc. into the balloon to inflate it. The balloon of this balloon catheter can be used for various purpose. For instance, it can be used for dilating and expanding a stenosed or contracted portion in blood vessels or for guiding the tip of the catheter body into any desired site with the pressure of the bloodstream acting upon the balloon.
The aforementioned balloon catheter is disclosed in, for example, U.S. Pat. No. 4,299,226 and Japanese Laying-Open Gazette No. 177,064/1984. FIG. 1 shows the manner in which the balloon catheter is used and selective hepatography is carried out. FIG. 1 shows a balloon catheter 30 comprising a catheter body 31 and a balloon 32 at the tip thereof. As shown in FIG. 1, contrast medium is injected into an affected part from the main passage opening at the tip of the catheter body 31. By using the balloon catheter in this manner, small lesions (e.g. the hepatic carcinoma A shown in FIG. 1), which could not be photographed with conventional angiography, can now be detected and transcatheter arterial embolization (TAE) and transcatheter arterial infusion (TAI) can now be conducted more safely and reliably. In this context, the embolization is surgical technique in an operation for hepatic carcinoma or the like where the blood flow to the affected part of the tumor or the like is stopped by blocking the artery, resulting in necrosis of the tumor.
However, for example, the case of hepatography of the abdomen or hepatic artery embolization, the hepatic artery tends to be constricted due to repeated insertion of the catheter. Accordingly, insertion of such a balloon catheter into the hepatic artery becomes difficult, so that the injection of contrast medium and the like becomes difficult. In another case, in which the proper hepatic artery branches off from the common hepatic artery at a very sharp angle, there are some difficulties in inserting the catheter into the proper hepatic artery, whereby adequate angiography of those area is impossible.
Japanese Patent Laying-Open Gazette No. 195470/1982 discloses a balloon catheter which comprises a catheter body having a main passage and an auxiliary passage and a balloon attached to the tip of the catheter body. The opening of the main passage is provided behind the balloon. The auxiliary passage leads to the balloon.
In the balloon catheter, the balloon is provided only for guiding the tip portion of the balloon catheter in blood stream by drifting through blood vessels, not for blocking the blood vessels.